What is the pH of a solution in which 15 mL of 0. 1M NaOH is added

1. What is the pH of a solution in which 15 mL of 0. 1M NaOH is added to 25mL of 0. 1M HCl?2. A buffer is prepared by adding 45. 0mL of 0. 15M NaF to 35. 0mL of 0. 1M HF. What is the pH of the final solution? (pKa of HF is 3. 14)3. What is the pH if the solution is 0. 1M NH3and 0. 1M NH4+? What is the pH if 12. 0mL of 0. 2M HCl is added?